Most of spinal cord-injured persons, who are incapable of moving their hands, cannot drive wheelchairs but utilize wheelchairs with the aid of assistants. Furthermore, it is difficult to acquire wheelchairs equipped with control units that can be used by spine cord-injured persons. Currently, there are few wheelchairs that can be used by spine cord-injured persons who are incapable of moving their hands.
For wheelchairs for handicapped persons, there have been proposed a wheelchair that can be controlled in such a way that a contact type or contactless type switch is mounted on a headrest and the movement of the head of a handicapped person is measured another type of wheelchair has a joystick mounted near the chin of a handicapped person and the joystick is controlled by the chin.
For example, U.S. Pat. No. 4,093,037 entitled “Head actuated control unit for battery-powered wheelchair” discloses a technique of controlling a wheelchair through the movement of the head of a handicapped person. A joystick is mounted on a headrest and a handicapped person controls the joystick by moving his or her head. Furthermore, an on/off switch is mounted on the headrest and a wheelchair is turned on/off in case of necessity.
U.S. Pat. No. 4,260,035 entitled “Chin controller system for powered wheelchair” discloses a technique of controlling a wheelchair by controlling a joystick using the chin of a handicapped person. This patent is constructed in such a way that an angle sensor is positioned behind the neck of a handicapped person and the angle sensor is connected to the chin of a handicapped person with a long bar. When a handicapped person moves his or her chin, the angle of the bar that is rotated according to the movement of the chin is measured, and a wheelchair is controlled according to the measured angle. For example, when a handicapped person moves his or her chin in a vertical direction, a wheelchair is controlled to move in forward and backward directions. In contrast, when the handicapped person moves his or her chin in a horizontal direction, the wheelchair is controlled to move in a lateral direction.
Although wheelchairs using the patented techniques have been marketed, most of handicapped persons feel uncomfortable about putting on a special apparatus that is not used by normal persons. Handicapped persons tend not to use wheelchairs equipped with control units that are exposed to the views of other persons. Further, the prior art technology is inconvenient in that handicapped persons control joysticks by moving their chins, or handicapped persons control joysticks mounted on headrests by moving their heads.